The invention relates to a method and system for detecting corrosion of an insulated corrosion prone object.
Inspection of insulated corrosion prone objects generally requires removal of at least part of the insulation layer to facilitate the inspection and subsequent reinstallation of the insulation layer.
International patent application WO 00/45148 discloses the use of corrosion sensors contained within the thermally insulating layer of a metal pipe, wherein the corrosion sensors comprise an electrochemical corrosion cell, an electrochemical noise measuring apparatus and/or an electrode assembly to indicate the presence of an electrolyte in the insulation layer, so that the known method uses the presence of an electrically conductive electrolyte as a tracer for the presence of corrosion of the metal pipe.
Japanese patent applications JP63079053 and JP58167948 disclose electrochemical and electrode assemblies for measuring corrosion of metal objects.
International patent application WO2008/047068 discloses a method for detecting moisture in an insulation layer surrounding an insulated vessel or pipe, wherein radially separated fiber optical Distributed Temperature Sensor (DTS) assemblies are configured to determine any differential temperature across the monitored section of insulation, which differential temperature is used as an indication of the possible presence of moisture in the insulation layer.
The paper “The two odors of iron when touched or pickled: (Skin) Carbonyl compounds and organophospines” published by D. Glindemann, A. Dietrich, H. J. Staerk and P. Kuschk in the magazine Angewandte Chemie, Edition 2006, 45, 7006-7009 discloses that phosphorus- and carbon-rich cast iron and steel under attack by acid emit a garlic-carbide metallic odor, which is dominated by volatile organophosphines and phosphine (PH3).
Other known methods for inspecting corrosion prone objects on the presence of corrosion are disclosed in UK patent application GB 2368914, Kroatian patent KR20060015152 and International patent application WO2009/126802.
There is a need for an improved method for inspecting insulated corrosion prone objects on Corrosion Under Insulation (CUI) in a substantially non intrusive manner, which does not require the use of complex electrode assemblies and which does not damage and/or require removal and reinstallation of the insulation layer.